Downhole wireless communication

A method comprising:

• flowing a first portion of a fluid from a container to a surface valve sub-assembly, the surface valve sub-assembly comprising:
• a first dump valve;
• a second dump valve, wherein the first dump valve and the second dump valve are in a parallel flow configuration;
• a surface controller communicatively coupled to the first dump valve;
• and
• a return line in fluid communication with the first dump valve;
• adjusting, by the surface controller, fluid flow through the first dump valve;
• adjusting, by the surface controller, a split of the first portion of the fluid between the first dump valve and the second dump valve;
• flowing, by the return line, the first portion of the fluid to the container;
• flowing a second portion of the fluid from the container to a downhole sub-system disposed within a wellbore, the downhole sub-system comprising a turbine-generator and a downhole controller coupled to the turbine-generator, wherein flowing the second portion of the fluid from the container to the downhole sub-system comprises flowing the second portion of the fluid through a coiled tubing fluidically coupled to the turbine-generator;
• receiving, by the turbine-generator, the second portion of the fluid;
• generating, by the turbine-generator, an output in response to receiving the second portion of the fluid;
• receiving, by the downhole controller, the output from the turbine-generator;
• and
• transmitting, by the downhole controller, a control signal in response to receiving the output from the turbine-generator.

A system comprising:

• a surface sub-system configured to receive a first portion of a fluid pumped by a pump positioned at a surface location, the surface sub-system comprising:
• a plurality of dump valves in a parallel flow configuration;
• a surface controller communicatively coupled to the plurality of dump valves, the surface controller configured to adjust fluid flow through each of the plurality of dump valves;
• and
• a return line in fluid communication with the plurality of dump valves, the return line configured to flow fluid from the plurality of dump valves to a container that provides feed to the pump;
• and
• a downhole sub-system configured to be disposed within a wellbore, the downhole sub-system comprising:
• a turbine-generator configured to generate an output in response to receiving a second portion of the fluid pumped by the pump;
• a circulation valve downstream of the turbine-generator;
• and
• a downhole controller coupled to the turbine-generator and communicatively coupled to the circulation valve, the downhole controller configured to adjust fluid flow through the circulation valve in response to receiving the output from the turbine-generator.